Advantages: Durable, less solution loss in the electrode.
Copper Sulfate Reference Electrode
Portable copper sulfate reference electrode is suitable for field use. It is mainly used for the determination of natural potential and cathodic protection potential of underground metal pipelines, the determination of stray current in the soil, can also be used to determine the potential of cable metal sheath and steel reinforcement in concrete. The electrode can be used as a reference electrode for the control potential of impressed current cathodic protection system in the sticky soil.It can be used in all kinds of soil and fresh water.
2. Structure Performance
(1) The electrode is small in size and easy to carry. The chamber is composed of transparent nylon rods for easy observation of the saturation of the copper sulfate solution.
(2) The electrode potential is stable, and the electrode is not easy to polarize.
(3) The electrode life is long, the electrode cap and the electrode cavity are connected by a screw, and the filling solution is convenient. The irrigation fluid can be used for more than one year at a time.
(4) The electrode structure is firm, the joints are corrosion-resistant, and the leakage rate of the microporous membrane is appropriate. There is no visible liquid flow, which can be placed in the pocket.
3. Use and Maintenance of Copper Sulfate Reference Electrode
First, the surface of the reference electrode should be kept clean. When not in use, the porous plug should be covered with a plastic bag or rubber cap to avoid contamination.Then, the copper sulfate inside is replaced regularly, and the non-metal grinding material is used to clean the rod. For example, clean copper rods with silica sandpaper instead of alumina sandpaper, and if the solution becomes cloudy, dump it and replace it with a new solution of copper sulfate. Make sure there are crystals in the solution that have not yet been dissolved. This saturated solution of copper sulfate prevents copper from corroding, thus stabilizing the electrode. After using the electrodes in a contaminated environment, they should be maintained. Contamination of chlorine compounds can alter chemical reactions. When the concentration is 5ppt, the reference potential becomes a mixed potential with a deviation of -20mv, and when the concentration is 100ppt, the deviation reaches -95mv. During the construction of cathodic protection engineering, one reference electrode should be prepared for standby, if the electrode is lost, another reference electrode can be used to continue the work.
When the reference electrode is used in the field, another new electrode should be prepared to calibrate the accuracy of the electrode used in the field. However, when there is more than 5mV between the value of the calibration electrode and the value of the reference electrode being used on site, it is necessary to clean the electrode used on the construction site.
Because the temperature and sunlight in the construction environment are different, it is necessary to correct the change of potential. It is necessary to record the temperature when reading the value of reference electrode. When the reference temperature value used is higher or lower than the actual temperature value, be sure to add or subtract 0.5mV/°F or 0.9mV/°C positive temperature correction when recording.
During the measurement using the reference electrode, the electrode should be shielded from direct sunlight. The transparent part on one side of the electrode can be covered with black tape. The value measured by the reference electrode varies with the degree of sunlight exposure. The potential of the reference electrode under good sunlight conditions is 10 to 50mV higher than that of the reference electrode in dark places where there is no sunlight.
In a particular environment, reference electrodes should also be selected according to the environment. For example, special reference electrodes on the inner wall of storage tanks are used to measure the cathodic protection potential on the inner wall of storage tanks or other water media. The special reference electrode is constructed by attaching a pure zinc bar to a porous, nonmetallic enclosure that ensures no direct contact between the electrode and the protected device. The potential of the special reference electrode for the inner wall of the storage tank is in the sleeve to avoid direct contact with the wall. The electrode potential is -1.10V CSE, with stable potential, drift or polarization less than 5%, and the structural protection potential should be lower than + 0.25V. The main components of the special reference electrode for the inner wall of the storage tank are: A1 less than 0.005%,Cd less than 0.003%, Fe less than 0.0014%, Cu less than 0.002%, Pb less than 0.003%, and Zn as the residual.